This invention relates to the preparation of tetraphenolic compounds. In one aspect, the invention relates to a process for preparing tetraphenolic precursors of low-chlorine epoxy resins suitable for high-performance electronics applications. In a specific embodiment, the invention relates to the preparation of the tetraphenol of ethane from glyoxal and phenol.
Tetraphenolic compounds such as the tetraphenol of ethane are starting materials for the preparation of multifunctional epoxy resins for electronics applications. The tetraphenol of ethane can be prepared by the acid-catalyzed condensation reaction of glyoxal and phenol in a homogeneous liquid reaction mixture. Typical acid catalysts include aqueous hydrochloric acid and oxalic acid. When aqueous HCl is the catalyst for the reaction, the acidic reaction product mixture is typically neutralized by addition of a base such as sodium hydroxide. The neutralized product mixture is then distilled for removal of excess phenol and by-products. The product yield of the desired tetrakis species is typically low, the reaction product being a mixture of di-, tri- and tetraphenolic isomers.
It is therefore an object of the invention to provide a process for preparing tetraphenolic compounds which permits recovery of the tetrakis phenolic species in relatively high purity. In one aspect, it is an object of the invention to provide phenolic precursors of low-chlorine epoxy resins for electronics applications.